The least changed part causing the most controversy appears to be the engine, which, according to the leaked info, retains the 2009 GT-R’s 478 HP power output. It had been rumored that the Spec V would make somewhere in the region of 520 HP. The engine does however receive an overboost function capable of temporarily boosting mid-range power for those trickier overtakes.

The biggest issue the Spec V appears to address is the GT-R’s immense 3,814 Lb curb weight. While a new figure wasn’t included in the leaked specs, the Spec V ditches the rear seats in favor of a carbon fiber shelf, also employing that material for the front seats, interior accents and aerodynamic aids. None of that sounds far-reaching enough to make a hugely meaningful reduction in mass however.

Nor does that minimal weight reduction do much to justify the massive increase in price. The leaked info indicates that the Spec V will retail in Japan for a massive $165,000 before tax, or nearly $95,000 more than the standard $69,850 GT-R.

Other changes include the elimination of the multiple transmission modes (presumably the Race setting will be chosen as the only one), carbon ceramic brakes, an exposed carbon grille, exposed carbon rear wing and exposed carbon ducts in the front splitter. A new paint color, Ultimate Black Pearl (dark purple), will be available for about $6,000.

According to the information, the 2010 Nissan GT-R Spec V is scheduled for official release on January 8, 2009. Hopefully it’ll bring with it some as-yet-unseen performance enhancement, or at least a slightly saner price tag. [GT-R World via GT-R Blog]